Interlocking electrical connector



May 5, 1953 F. E. MAXWELL INTEBLOCKING ELECTRICAL CONNECTOR 3Sheets-Sheet 1 Filed. July 11, 1949 INVENTOR, J/efc/zeri i/Zaxzaell y 5,1953 F. E. MAXWELL 2,637,764

INTERLOCKING ELECTRICAL CONNECTOR Filed July 11, 1949 3 Sheets-Sheet 2INVENTOR, jlefc/zer 5772mm]! HTTORNEK 7 Patented May 5, 1953 UNITEDSTATES Parent OFFLCFE.

INTE RL OCKIN G ELECTRICAL .1 CONN EGTOR;

Fletcher E. Maxwell, Glendale; Calif;

Application l uly L1, 1949, Serial No. 104,067

This invention relates to. so-called. socket. connectors for electricalconductors. andparticularly to an improved form thereoiiin which theconnecting elements are interlocked with each other incident tocompletion of the electrical connection.

An object. of the: invention is to. provide a, plug and socket type ofelectrical conduct'orconn'ect ing means which: is so constructed andarranged that the elements are first inserted one within the otheran'dgiven a relatively'rotary movement to eifect the. electrical connection.

Another'object of the invcntionisto provide a plug and socket type ofconnector for electrical conductors in which the wall socket portionisso constructed and arranged that'it may be installed in a conventionaloutlet box inthe same manner as conventional wall socket units.

Still anoth'erobjeot of the invention is' to provide a plug; elementwhich is adapted foruse with the above wall socket" and which, further,is' so constructed and arranged that two conductorsmay be interconnectedwith identicalplugs;

A still further object or theinventionis to provide a plug and sockettype of connecting means for electrical conductors in which the livecontact point is shielded toprevent accidental contact therewith.

Still another object of the invention is to pro-- vide a plug and socketty e of connecting means for electrical conductors in which the two*elements to be connected have identical; semi-cir cula'r matingprojections and socket portions and having the contact elements housedor' guarded by the semi circular' projections insuch mannerthatthecontacts are interengaged by relative rotation of the connectingelements.

Still. another object of the inventionis to: provide a. connecting meansfor electrical conductors comprising awall socket element and a; plugtype. element which: may. be engaged with" said wall socket orwith anidentical plug element;

A still further object of the invention is taprovicle. a: connectingmeans? adapted to: connect-plugs and; sockets of: the type comprisingthe. present invention with conventional. screw type plugs and sockets}.

Still. another object of the invention. is. tozpro;- vide a. connectingmeans; foireleetrlcal conductors which the above: enumerated: objects;are achieved and which issimple and economical to. manufacture and.install and which: is both. safe and reliabl ineuse.

' With thev above objects iniview together with such. other objects.and. advantages as. may subsequently appear, the invention resides inthe parts, and in the construction, combination and arrangement ofpartsdescribed, by Way of. example. in the following.- specificationand? illustrated, alsoby, way of example in the accompany,- ing'drawings: which form a part. of said specifi cationand in.wliichdrawings:

Fig. 1. isa front. elevation of a WaIISOCkBUaSrsemblyembodying theinvention,

Fig. 2 is an enlarged, sectional top-plan. view taken on the line 2.2-ofFig.. 1,.

Fig. 3-. is. a-iront-elevation. of a. wall socketassembly mounted in. aconventional outlet box,.

Fig. fisasicle elevationof the wall socketassemblv; the associatedoutlet. box. being shown insection-on thelinell liof. Fig. 3,,

Fig. 5.1is. a rear, sectional elevation taken; on. the lines 5-5of.Figs..2land 4,.

Figs, 6. and? are side elevationsof themating faces. of. the,v contactcarrying assemblies of the Wall. socketstructure. as indicated. by the.arrows 6.6" and.lll,.respec.tively,,onFig. 5,.

Fig. 8. is an. exploded. view of the. component parts. of'one of thecontact carrying. assemblies; the. parts being shown in front elevation,

Figs. 9. and. 10 are sectional front. elevations. on the lines iii-Qand. iii-All? of. Fig. 2;, respectively, showing. the upper socket ofthe wall. socket open and.v the. lower socket engaged by a. plug elementand theinter-engagement of the plug and' socket contact elements- Fig;11 isacontactemi elevation of'a plugfelem'ent'. adapted for cooperationeither with. the socket assembly shownin Figs. 1 to 10; inclusive, orwith another plug having identical contact means,

Fig; 1'2 is a side elevation, partly. in section, of the plug shown inFig. 1.1,v

Fig. 13 is an opposite endelevati'on' of the plug shown in Figs: 11 and12,

Fig: 14 is a side" elevation of the contact carrying assembly" of theplug; the View being taken from the-same direction as" Fig; 12,

Fig. 1551 is an end elevation of the assembly sliown in Fig. 1'4;showing theconductor-attacm. ing means carried by the contact elements,

Figs; lfi 'and 1 7 are side elevations' oi-the mating. faces of: thecomponent: parts of. the contact assembl'yof the plug;

Eigsz. 18. and 19. are. transverse sectional. views taken on the linesIii-I28 and i:9|'9 of:Fig.. 1 2; respectively,

Fig. 2.0 is. a; socket;- encl elevation. of" anadapter having. at one,end a'. contact means such as: em.- ployed the present invention and at;the other. a. conventionalwinternally threaded: socket to receive a lampor the like,

Fig. 21 is a medial sectional elevation taken on the line i9l9 of Fig.20,

Fig. 22 is a medial section taken on the line 2222 of Fig, 21,

Fig. 23 is an elevation of the externally threaded end of another formof adapter,

Fig. 24 is a medial elevation taken on the line 24-24 of Fig. 23,

Fig. 25 is a medial section taken on the line 25-25, of Fig. 24,

Fig. 26 is a side elevation showing the endwise relative movementincident to the interengagement of two identical plugs; partly completedportions of the casing elements of the plugs being broken away forclearness of illustration, and

Fig. 27 is a view similar to Fig. 25 but showing both the endwise androtative movements completed.

Referring first to Figs. 1 to inclusive there is shown a wall socketassembly adapted for use in conventional outlet boxes. The assembly ismounted in a wall W including a studding W having an outlet box Bmounted thereon by a nail or screw N. Leads L and L extend through aconduit C to the outlet box and are secured to the binding post screws Pand P" of the assembly. The front of the asssembly is covered by aconventional cover plate F, having the usual openings formed therein andwhich is secured in place by means to be later described in detail.

The socket assembly per se is formed of nonconductive material and athin rectangular base member I having recessed side portions 22 andhaving a rib 3 rising from one face thereof around its sides exceptwhere interrupted by the recesses 2-2, a combined contact carrying andshield element 4, a side wall element 5 and a second sidewall andcontact carrying element 6; all of said elements having interfittingfaces so arranged as to hold them in alignment for mounting in an outletbox. The sides of said members 5 and 6 are each provided with clearancespaces 5a and 5a, respectively, disposed in alignment with the recesses22 in the base member I. The mounting means comprises a. U-shaped metalstrap I having out-turned perforated end portions 83 adapted to besecured to the usual in-turned ear portions E of the outlet box byscrews S threaded into the ear portions E, E of the outlet box (see Fig.4). A screw 3 having its head adjacent the strap 1 and passingtherethrough and thence through aligned holes H], II, i2 and [3 in themembers I, 4, 5 and 6, respectively, and thence through a hole in thecenter of the cover plate F and engaged by a nut 3' at the exterior ofthe cover plate serves to hold the socket assembly together and securedto the strap 7.

The member 6 rests on and extends along one side of the base plate i andon its rear face is provided with a recess I4 into which the locatingrib 3 extends (see Fig. 2) and the outer side face and the ends of themember are in alignment with the corresponding side and end edges of thebase plate. The rear face of the member is provided with a groove l5 toreceive a contact member 16 one end of which carries the binding postscrew P and the contact portion of which is bifurcated and includesoutwardly extending shanks I? and is which terminate in laterallyextending contact portions i1 and I8 disposed within vertically disposedrecesses i9 and 26 formed in semi-circular bosses 2| and 22 at the outerface of the member 6. Spaced from the curved portion of the periphery ofthe bosses 2| and 22 are skirt portions 23 and 2t, respectively theouter ends of which extend through one side of each of the openings 0 inthe coverplate F and the grooves 25 and 26 between the adjacent faces ofthe respective bosses and skirt portions are adapted to receive annularflange portions of the plug assembies used with these sockets as will belater described in detail. In rear of the bosses 21 and 22, the memberis cut away to form recesses 21' and 23 of segmental outline adapted toreceive a portion of the cooperating plug element incident to rotationof the plug element after insertion into the socket in the manner to belater described. Preferably, the element 6 is moulded from a suitableplastic or ceramic material with the contact member moulded in place.

The rear face of the element 4 rests on and covers all of the surface ofthe base member 1 not covered by the element 8 and is provided with agroove 29 which mates with the rib 3 on the base member. On the edgethereof adjacent the element 6 the element 4 carries two inverted L-shaped members 33 and 38 disposed so that one face thereof lies againstthe flat side face of each of the bosses 2| and 22 as best shown inFigs, 3 and 9, and the shank portions cover the grooves in the member 6in which the shanks H and I8 of the contact members 11 and 18 are housedas shown in Fig. 10. The outer, wider portions of the members 33 and 3|are each provided with narrow rectangular slots 32 and 33 disposedopposite the contact member recesses l9 and 20 in the element 6 and areso disposed that a contact element on a plug will enter through the slotand engage the contact element in the element 6 upon rotation of theplug as will later be described. Also extending outwardly from the basemember 4 at an acute angle to each of the members and 3i are thin wallmembers 34 and 35 so disposed that one flat side thereof lies againstthe walls 38 and 3'! of the recesses 27 and 23.

The element 4 is preferably moulded and is formed from non-conductivematerial and has incorporated therein a bifurcated conductor 38 carryingthe binding post P at the juncture of the two arms 39 and 40 thereof.The arm 39 extends along and flush with the rear face of the element 4to a point 4! opposite the mid width of the member 34 and thence extendsdirectly to the outer face of that member, thence parallel to and alongthe face of the member 34 and across the end thereof and terminates in acontact portion 42 which lies at about the middle of the recess 2'! andwhich i spaced from and curved about the axis of the socket. The arm 40extends directly to the mid width portion of the member 35 and thencealong the outer face and across the end of the member 35 and terminatesin a contact portion 43 which is similarly disposed in the recess 23. Itwill be noted in Fig. 8 that the free ends of the contact portions donot extend beyond the faces of the L-shaped members 30 and 3! which areremote from the members 34 and 35.

The element 5 has a flat inner face 44 adapted to rest on the outer faceof the element 4 and is provided with dowels 45 adapted to engage holes46 in the member 4 to hold the two elements in alignment. The element isformed with larger and smaller circular surfaces 41 and 48 which aregenerated about the same centers as the grooves 25 and 26 and which formledges 49 and 50 at the same level as the bottom of the grooves. Thesecurved surfaces together with the adjacent faces of the members 30 and3| form semicircular sockets 5| and 52 adapted to receive the plugs forwhich these sockets are adapted. Additionally, the element 5 includescurved outwardly projectingskirt portions 53 and 54 which projectthrough the cover plate F at the sides of the socket openings, oppositethe skirt portions 23 and 24, respectively.

Between the sockets 5i and 52 the element 5 is provided with a laterallyextending tongue portion 55 through which the hole 42 extends and themember 6 is provided with an oppositely laterally projecting tongueportion 56 which overlies the tongue portion 55 and through which thehole 13 extends. Also, each end face of the element is provided withlaterally extending tongues 5'! and 5B which engage suitable notches 59and Ed in the ends of the element 5 to assist in holding theseveralparts or the socket in alignment for insertion of the screw 9. Thusthrough the various interlocking faces including the rib 3 on the baseplate i, the mating grooves 14 and 29 on the elements it and 4, thedowels on the element 5 engaging the holes 46 on the element i, thmeeting faces of the elements 4, 5 and 6 together with the tongues andgrooves on the ends thereof make it possible for the entire assembly tobe held together for assembly with the strap l and screw b. At the sametime, the conducting elements iii and 38 are completely insulated fromeach other and are covered except for the various contact points and thenecessarily exposed binding post portions. The wall socket assembly isthe same size as conventional wall socket assemblies, and is installedin conventional outlet boxes in the conventional manner. The bindingposts are located in the conventional position so that no special skillis required to make the installation.

Referring now to the plug assembly portion of the invention andparticularly to Figs. 11

to 19, inclusive there is shown a plug adapted to be attached to a lightcord or similar conductor and to be connected to and disconnected from awall socket assembly of the type above described or to be connected toor disconnected from an identical plug assembly. The plug assemblyincludes a cylindrical casing ti formed of non-conductive materialhaving at one end a reduced diameter bore 62 through which the end ofthe conductor extends for attachment to the binding posts. Mounted inthe larger bore 63 of the casing is the contact carrying and shieldingassembly comprising elements M and 65 which have semicircular bodyportions (it and 57 which, when the elements are assembled, comblue toform a circular outline that fits snugly within the bore E3 and to restagainst the end wall 68.

The element St at its inner end is formed with two segmental recesses $9and it divided by a centrally disposed wall member 1i and the inner endof the element St is provided with similar recesses 69' and lil' dividedby a similar wall member H and when the two elements are assembled,these recesses combine to form sectorshaped housings for the bindingpost ends of the contact members '12 and i3 separated by the wallmembers ii and H (see Figs. 15 and 16); portions of the wall membersextending through the bore 62vto separate the leads of the cord to whichthe plug is attached.

The element 64 includes a sector shaped portion M which extends beyondthe end of the easing 6! and this portion 64 from about the plane of theend of the casing to a point within the casing is undercut to provide arecess I5 through the sidewall 76 of which the contact end 7'! of thecontact member 72 projects (see Figs. 16 and 18). The element 64 isprovided with a groove ill which leads from the recess 69 parallel tothe axis of the plug thence angularly laterally to a second parallelportion and thence at right angles to and through the wall it: and inthis groove the contact member i2 is losely positioned (see Figs. 16 and18). The contact member 13 extends from the binding post cavity it, illalong a groove '5' formed in the member 84 and extending parallel to thelength thereof and terminating in a laterally disposed sector-shapedrecess 86 in which the contact portion 8! of the member iii is disposed(see Figs. 16 and 19).

The element .65 is generally similar to the element St from the bindingpost end to a point even with the inner wall 82 of the recess 75: andfrom that point extends outwardly as a thin inverted L-shaped portion 83the outer face of which intersects the axis of the plug assembly and theinner face of which overlies and covers the grooves l8 and i9 and therecess 86 except for a rectangular opening EM opposite the recess 8i?for the entrance of a contact point of another plug or socket. Theelements 6 and 65 with the contact members 12 and it are held inassembled relation by dowels 35 and 86 on the member which engagecorresponding holes t? and 35 in the meeting face of the member 65 (see1i) and the assembly is then placed in the casing 6i and secured thereinby a screw 89 which extends through holes Bil and 3! in the members and65 and is threaded into the opposite wall of the casing at 92 (see Fig.12).

The mode of effecting a connection between the plug and socket isillustrated in the lower portions of Figs. 9 and 10. The plug is firstinserted endwise into the socket with the semicircular portion thereofentering the correspond- .ing portion of the socket and with thesemi-circular boss 22 of the member 6 entering the corresponding socketor clearance portion of the plug; the groove 25 receiving the skirtportion 93 of the plug casing to permit this endwise movement. The plugis then rotated clockwise as viewed in these figures and upon suchmovement the contact point Tl on the plug will enter the slot 33 in themember 3i and engage the contact point i8. Simultaneously, the member 83will move over the end of the contact point 43 bringing the contactpoint 8i into engagement therewith to complete the electricalconnection. It is to be noted that when thus engaged the plug and socketare interlocked and can not be separated without first rotating the plugto efiect breaking the circuit. In installation of the socket it ispreferable that the hot wire be connected to the binding post P so thatthe hot contact points ii and it associated therewith are those that areshielded by the members to and 3|. It will be further appreciated thatthis novel construction permits the direct interconnection of identicalplugs since the semi-circular projec tions of each will enter thesemi-circular recesses of the other whereupon relative rotation of theplugs (see Figs. 26 and 27) will interlock the plugs with incidentinterengagement of the contacts Ti and SI of one plu with the contactsBi and H respectively of the other plug. It will be appreciated that inpreparing cords having these plugs at each end, if the contacts arereversely connected to the conductors, the safety 7 feature of havingthe "hot contact shielded will be preserved.

Referring now to Figs. 20, 21 and 22, there is shown an adapter toconnect a plug of the type forming part of the present invention with aconventional internally threaded socket such as a lamp socket. In thisform of the invention the internally threaded metal shell 94 is mouldedin place in a cylinder or casing 95 having a wall portion 95' extendingacross it intermediate its ends. The shell 94 has a laterally extendingtongue portion 96 through which a rivet 91 disposed in the Wall 95extends and the other end of the rivet is engaged by the out-turned end98 of the contact element 99 which is generally similar to the elementI2 in the previously described form of plug assembly. A second rivet Iextending through the wall 95 at a point diametrically opposite therivet 91 secures a contact element IOI adapted to engage the centercontact of a light bulb or other connecting element screwed into theshell 94 and at the opposite side of the wall 95 the rivet I00 isengaged by the out-turned end I02 of a contact element I03 which isgenerally similar to the contact element I3 in the plug assembly shownin Figs. 11 to 19. The members I04 and I05 in which the contact elements99 and I03 are housed are generally similar to the members 64 and 95,respectively, except that the portions that formed the cavities for thebinding posts and the dividing wall between the cavities are dispensedwith. A screw I06 extending through one wall of the casing 95 thencethrough holes I01 and I08 in the members I04 and I05 and threadedlyengaging the opposite wall of the casing holds the parts in assembly.

Referring now to Figs. 23, 24 and 25, there is shown an adaptation ofthe plug element of the present invention to an externally threaded plugfor engaging the conventional type of screw threaded socket. In the formshown, an externally threaded sleeve I09 is molded in place on a casingmember IIO which is in the form of a hollow cylinder having a largerdiameter portion III at one end and a smaller diameter portion I I2 atthe other end which terminates in an end wall H3. The outer face of thisend wall is provided with two diametrically opposite notches or recessesH4 and H5 into one of which a laterally extending tongue portion IIG ofthe sleeve I09 extends and is engaged by a rivet I I! extending throughthe end wall II3. A contact element I I8 having a portion thereofextending over the center of the end wall I I3 is disposed in the recessI15 and secured therein by a rivet H9 mounted in the end wall II3. Thecontact assembly is similar to that shown in Figs. 20, 21 and 22 exceptthat the contact elements I20 and I2I are formed with extensions havingS-shap-ed bends formed therein terminating in out-turned portions I22and I23 so that they will engage the heads of the rivets H9 and I I!respectively, with sufficient pressure to insure proper contact. Theparts are held in assembly by the screw I06 in the same manner as shownin Figs. 20, 21 and 22.

While in the foregoing specification I have described a specific mode ofexecution Of my invention, it will be understood that this is by way ofexample and that I do not intend thereby to be limited to the exact formdisclosed and that the invention embraces all such modifications of theparts and of the construction, combination and arrangement of parts asshall come within the purview of the appended claims.

I claim:

1. A connector for electrical conductors comprising a pair of assemblieshaving identical interengaging and contact effecting elements; each ofsaid assemblies comprising a semi-cylindrical plug portion and a plugreceiving socket having a plug receiving opening disposed with the flatside thereof in juxtaposition to the flat side of said plug; said plugwithin said opening being reduced segmentally in cross section withresultant increase of said socket to segmental form of greater thansemi-circular extent, a first contact member projecting into saidsocket, a second contact member housed within said plug and terminatingin a contact surface adjacent the outer end of said plug, and an openingin a side wall of said plug opposite said contact surface through whichsaid first contact member of one of said assemblies may enter and engagesaid contact surface of the other assembly when said assemblies areinterengaged with the plug portion of each assembly disposed in thesocket portion of the other assembly.

2. A plug and socket connected means for electrical conductorscomprising a wall socket assem bly adapted to be mounted in aconventional outlet box and having a pair of binding posts forconnecting it to a source of electrical energy and having a base portionsupporting a plurality of sockets for engagement with connector plugs,each of said sockets including a semi-cylindrical plug receiving recessand a semi-cylindrical plug portion disposed with its fiat side formingthe flat side of said semi-cylindrical recess; each of said plugportions adjacent the bottom of said semicylindrical recess being cutaway to form a segmental shaped recess, a plurality of contact membersdisposed one in each of said segmental shaped recesses connected to oneof said binding posts and a plurality of contact members disposed one ineach of said semi-cylindrical plug portions and connected to the otherof said binding posts, and a plug element constructed and arranged toengage said sockets.

3. A plug and socket connector means for electrical conductorscomprising a plug element having a pair of binding posts for connectionto the leads of a lamp cord or the like at one end thereof and having asemi-cylindrical recess at the other end with a semi-cylindrical plugportion disposed adjacent to said recess with the flat side of said plugportion forming the fiat side of said recess; said plug portion adjacentthe bottom end of said semi-cylindrical recess being cut away to form asegmental shaped recess, a contact member connected to one of saidbinding posts and extendin into said segmental shaped recess, a secondcontact member connected to the other of said binding posts andextending into said semicylindrical plug portion, and a slot in the flatside face of said plug portion affording access whereby a contact memberof another connecting means may enter for engagement with said secondcontact member.

4. A plug and socket connector means for electrical conductorscomprising a wall socket assembly adapted to be mounted in aconventional outlet box and having a pair of binding posts forconnecting it to a source of electrical energy, said assembly comprisinga base plate, having a peripheral rib, a contact carrying member havinga thin base portion engaging the rib on said base plate and a pair ofinverted L-shaped flange portions and a pair of shorter flange portionslying in planes intersecting the planes of said 9 i inverted L-shapedflange portions at acute angles, a' contact element carrying one of saidbinding posts mounted on said contact carrying element and havingcontact points overlying said smaller flanges, a socket forming elementmounted on the base of said contact carrying element and having curvedwall portions which cooperate with inverted L-shaped flanges to definesemi-cylindrical recesses, a second contact carrying eiement mounted onthe base plate adjacent to said first contact carryin member and saidsocket for1ning element and engaging the rib on said base plate; saidsecond contact carrying member having face portions which mate with theouter sur-- faces or" said flanges, a contact element carrying saidother binding-post mounted in said second contact carrying member andhaving contact portions housed in recesses in said mating faces, a slotin each of said'inverted l.--shaped flanges opposite said last namedcontact points and a screw passing through said base plate, both of saidcontact carrying members and socket forming member effective to holdsaid members in assembled relation, and a detachable plug havingcorrespondin semi-cylindrical plug and socket means adapted to beconnected with and disconnected from said assembly.

5. A plug and socket connector means for electrical conductorscomprising a wall socket as sembly adapted to be mounted in aconventional outlet box and having a pair of binding posts forconnecting it to a source of electrical energy, said assembly comprisinga base plate, having a peripheral rib, a contact carrying member havinga thin base portion engaging the rib on said base plate and a pair ofinverted L-shaped flange portions and a pair of shorter flange portionslying in planes intersecting the planes of said inverted L-shaped flangeportions at acute angles, a contact element carrying one of said bindingposts mounted on said contact carrying element and having contact pointsoverlying said smaller flanges, a socket forming element mounted on thebase of said contact carrying element and having curved Wall portionswhich cooperate with said inverted L-shaped flanges to definesemi-cylindrical recesses, a second contact carrying element mounted onthe base plate adjacent to said first contact carrying member and saidsocket forming element and engaging the rib on said base plate; saidsecond contact carrying member having s-ec tor shaped plug formingportions, the flat faces of which mate with the faces of said invertedL-shaped portions to form semi-cylindrical plug portions of thesubstantially same cross-sectional area. as said sockets, a contactelement carrying said other binding post mounted in said second contactcarrying member and having contact portions housed in recesses in saidsector-shaped portions, a slot in each of said inverted L.-shapedflanges opposite said last named contact points and a screw passingthrough said base plate, both of said contact carrying members and saidsocket forming member effective to hold said member in assembledrelation, and a detachable plug having corresponding semi-cyiindricalplug and sock et means adapted to be connected with and disconnectedfrom said assembly.

6. A plug and socket connector means for electrical conductorscomprising a cylindrical, non conductive casing element having atransverse wall portion intermediate its ends, an internally threadedmetal sleeve mounted in one end of said casing having a laterallyextending portion en gaged by a rivet extending through said wallportion, a contact element mounted on said wall portion by a secondrivet extending through said wall portion at a point remote from said,first named rivet and having a portion thereof disposed at the center ofsaid end wall, connecting means at the other end of said casingcomprising two members having semi-circular base portions disposed insaid casing and secured in said casing by a screw extendingdiametrically acros said casing and both of said base portions; one ofsaid members having a sector-shaped portion extending beyond said casingand having a segmental shaped recess formed therein adjacent said baseportion, a first contact member mounted in a groove in said one memberhaving one end in engagement with one of said rivets and the other endextending into said segmental shaped recess, a second contact membermounted in a second groove in said one member having one end inengagement with the other of said rivets and having the other endthereof disposed in a sector shaped recess in said sector shapedportion, the other of said members having a flange portion of invertedL-shape disposed with one side there of adjacent the flat face of saidone member; said inverted L-shaped portion covering the grooves in saidone member and having a slot formed therein opposite said sector shapedrecess to admit a contact of another connecting assembly for engagementwith contact portion in said recess; said sector shaped portion of saidone member and said inverted L-shaped flange of said second membertogether forming a plug portion of semicylindrical cross section and thespace between the wall of said. casing and the side of said flangeforming a semi-cylindrical recess of substantially equal cross sectionadapted to engage a connecting element having identically disposedsockets, and plug elements.

'7. A plug and socket connector means for electrical conductorscomprising a cylindrical shell having a reduced diameter opening at oneend for entrance of a conductor and having inserted from the other endtwo members "raving semicylindrical base portions secured therein by ascrew extending diametrically across said casing and said base por ions,one of said members having a sector shaped portion extending beyond saidcasing and having a segmental-shaped recess formed therein adjacent thebase portion of said member, a first contact member mounted in a groovein said one member, a contact member disposed in said groove andextending from a binding post carried by said contact member adjacentsaid reduced diameter opening along said groove and terminating in acontact point disposed in said segmental shaped recess, a second groovein said one member, a second contact member disposed in said secondgroove and extending from a binding post carried by said second contactmember adjacent said reduced diameter opening along said second grooveand terminating in a contact portion disposed in a recess in said sectorshaped portion; the other of said members having a flange portion ofinverted L-shape disposed with one side thereof adjacent the flat faceof said one member; said inverted L-shaped portion covering the groovesin said one member and having a slot formed therein opposite said sectorshaped recess to admit a con tact of another connecting assembly forengagement with contact portion in said recess; said sector shapedportion of said one member said inverted L-shaped flange of said secondin niber together forming a plug portion of semi-cylindrical crosssection and the space between the wall of said casing and the side ofsaid flange forming a semi-cylindrical recess of substantially equalcross section adapted to engage a connecting element having identicallydisposed sockets, and plug elements.

8. A connector means for electrical conductors comprising two assemblieseach having a pair of contact elements including means for attachment toa pair of conductors, each of said assemblies having a semi-cylindricalplug portion and an adjacent semi-cylindrical socket portion, having anend wall; the curved faces of said portions being generated about acommon axis and the plug portion of each assembly being insertable intothe socket portion of the other assembly; each of said plug portionshaving a segmental shaped recess cut in one side thereof; said recessextending from the plane of said end wall axially of said plug portionto a point slightly in excess of the length of said plug portion; one ofsaid contact members in each of said assemblies terminating in a contactpoint projecting into said segmental shaped recess and the other of saidcontact members terminating in a recess formed in the outer end of saidplug portion and positioned to be engaged by the first named contactmember of the other assembly when the two assemblies are inserted onewithin the other and given a relative rotative movement; the segmentalshaped recesses of each assembly providing clearance space for thatportion of each of the plug portions which overlie the said recesses andcertain of the interengaging faces of said plug portions and saidrecesses when interengaged serving to absorb all stresses incident toforces tending to separate said assemblies by direct pull parallel tosaid axis.

9. A connector for electrical conductors comprising a pair of assemblieshaving identical interlocking and contact effecting elements; each ofsaid assemblies comprising a semi-cylindrical plug portion and a plugreceiving socket having a semi-cylindrical plug receiving openingdisposed with the flat side thereof in juxtaposition to the flat side ofsaid plug portion; said plug portion within said opening being reducedsegmentally in cross section with resultant increase of said socket tosegmental form of greater than semi-circular extent, a first contactmember having an electrical contact effecting surface disposed in saidsocket and lying in a plane normal to the axis about which the curvedsurface of said plug portion is generated, a second contact memberhaving an electrical contact effecting surface disposed wholly withinsaid plug and lying in a plane parallel to the plane of said firstcontact member, and an opening in a wall of said plug portion oppositesaid second named contact surface through which said first named contactmember may enter and bring said contact effecting surfaces together whensaid assemblies are interengaged with the plug portion of each disposedin the socket of the other and subjected to relative rotation; the entryof said first contact members into said openings in said plug wallsserving to interlock said assemblies against separation while saidcontact surfaces are interengaged.

FLETCHER E. MAXWELL.

References Cited in the file of this patent UNITED STATES PA'IENISNumber Name Date 366,654 Duby July 19, 1887 367,931 Runels Aug. 9, 18871,265,163 Bahls May 7, 1918 2,015,715 Doane Oct. 1, 1935 2,190,230 ColeFeb. 13, 1940 2,197,981 Meston Apr. 23, 1940 2,386,177 Andersen Oct. 9,1945 FOREIGN PATENTS Number Country Date 10,260 Great Britain of 1891

